Restrictive flow area section in an intake passage of a well pump

ABSTRACT

A well pump assembly has a pump housing with an intake member. A barrel has a barrel head secured to and extending downward from the intake member. A plunger is reciprocally carried in the barrel bore. An intake passage extends coaxially in the intake member and the barrel head into the barrel bore above the plunger. An intake port extends from an exterior of the intake member to the intake passage. A nozzle is secured within in the intake passage. The nozzle has an orifice passage with a downward converging section extending downward to a constant diameter section. The constant diameter section has a smaller diameter than the intake passage.

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority to provisional application Ser. No.62/482,511, filed Apr. 6, 2017.

FIELD OF DISCLOSURE

The present disclosure relates to well pumps. More specifically, thepresent disclosure relates to a reciprocating pump having an orificewith a restrictive flow area within an intake passage for separatinggas.

BACKGROUND

Submersible pumping systems are often used in hydrocarbon producingwells for pumping fluids from within the wellbore to the surface. Thesefluids are generally liquids made up of produced liquid hydrocarbon andoften water. One type of system used in this application employs anelectrical submersible pump (“ESP”) system. ESP systems include a pumpoperated by an electrically powered motor for pressurizing the fluid.Pressurized fluid is discharged from the pump and into productiontubing, or by other means, for conveyance to surface.

The types of ESP systems in wellbores generally include centrifugalpumps, progressive cavity pumps, reciprocating pumps, and positivedisplacement pumps. Centrifugal and progressive cavity pumps are usuallyequipped with a rotating impeller or helical rotor to urge the fluidfrom downhole to the surface. The reciprocating pumps and positivedisplacement pumps typically operate by reciprocating a plunger to forcewellbore liquid up hole. In any of these designs, vapor lock can occurwithin the pump when a sufficient amount of gas accompanies the liquid,so that forces applied to the liquid merely compress the gas rather thancausing the fluid to be lifted to surface.

SUMMARY

A well pump assembly has a pump housing having a longitudinal axis. Anintake member is secured to the pump housing. A discharge member with adischarge passage is secured to the pump housing. An intake passage inthe intake member draws well fluid into the pump. A fluid movingmechanism is operatively located between the intake passage and thedischarge passage to propel the well fluid out the discharge passage. Anorifice in the intake passage has an orifice passage with a downstreamdirection converging section extending from the intake passage to aconstant diameter section. The constant diameter section has a smallerdiameter than the intake passage.

In one embodiment, the orifice comprises a nozzle containing the orificepassage and secured within the intake passage. In this embodiment, thenozzle is secured within a downstream end of the intake passage. Theconverging section of the orifice passage has an upstream end with adiameter equal to a diameter of the downstream end of the intakepassage.

Also, in this embodiment, the orifice includes an annular upstreamfacing shoulder at a downstream end of the intake passage. An orificebore extends through the upstream facing shoulder. The nozzle has anozzle upstream portion and a nozzle downstream portion. The nozzleupstream portion has a larger outer diameter than an outer diameter ofthe nozzle downstream portion, defining a downstream facing shoulderthat rests on the upstream facing shoulder. The outer diameter of thenozzle upstream portion may be the same as the diameter of the intakepassage. The outer diameter of the nozzle downstream portion may be thesame as the diameter of the orifice bore.

In a second embodiment, the nozzle is not employed in the orifice. Theorifice has a downstream direction diverging section that joins andextends downward from the constant diameter section of the orificepassage.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B comprise a sectional view of a reciprocating pump havinga nozzle inlet passage in accordance with this disclosure.

FIG. 2 is an enlarged sectional view of a portion of the pump of FIGS.1A and 1B.

FIG. 3 is an enlarged sectional view of a portion of the pump of FIGS.1A and 1B, but showing a square edge orifice inlet passage.

While the disclosure will be described in connection with twoembodiments, it will be understood that it is not intended to limit thedisclosure to these embodiments. On the contrary, it is intended tocover all alternatives, modifications, and equivalents, as may beincluded within the scope of the disclosure as defined by the appendedclaims.

DETAILED DESCRIPTION

The method and system of the present disclosure will now be describedmore fully hereinafter with reference to the accompanying drawings inwhich embodiments are shown. The method and system of the presentdisclosure may be in many different forms and should not be construed aslimited to the illustrated embodiments set forth herein; rather, theseembodiments are provided so that this disclosure will be thorough andcomplete, and will fully convey its scope to those skilled in the art.Like numbers refer to like elements throughout.

It is to be further understood that the scope of the present disclosureis not limited to the exact details of construction, operation, exactmaterials, or embodiments shown and described, as modifications andequivalents will be apparent to one skilled in the art. In the drawingsand specification, there have been disclosed illustrative embodimentsand, although specific terms are employed, they are used in a genericand descriptive sense only and not for the purpose of limitation.

Referring to FIG. 1A, pump 11 attaches to a string of production tubing13 that supports pump 11 in a well. Pump 11 has a discharge head 15 witha discharge passage 17 that discharges well fluid into production tubing13. In this example, a tubular intake member 19 secures by threads tothe lower end of discharge head 15. A standing valve 21 has a lower endsecured by threads to the upper end of intake member 19. Standing valve21 includes a cage 22 containing a ball or valve element 23. Ball 23 hasa closed position against a seat 25 below ball 23 in cage 22; in theopen position, ball 23 moves above seat 25. Seat 25 is at the upper endof a valve passage 27 extending through standing valve 21.

Intake member 19 has an intake passage or cavity 31 that is a constantdiameter cylindrical passage concentric with pump axis 33. Intake ports35 (one shown by dotted lines) extend to intake cavity 31 from theexterior of intake member 19. Intake cavity 31 has a closed upper endjust above the junction where intake ports 35 join intake cavity 31.Discharge passages 37 extend upward from the lower end of intake member19 to valve passage 27. Discharge passages 37 are spaced around intakecavity 31 and do not connect with intake ports 35 or intake cavity 31.

Pump 11 has a cylindrical housing 39 that secures by threads to intakemember 19 and extends downward. Housing 39 encloses a barrel head 41that has an internally threaded receptacle 40 on its upper end.Referring to FIG. 2, a depending neck 42 of intake member 19 insertsinto receptacle 40 and secures to the internal threads. Barrel head 41has an orifice bore 43 extending coaxially downward from the lower endof barrel head receptacle 40.

Orifice bore 43 has an upper portion 43 a and a lower portion 43 b,which extends downward from upper portion 43 a. In this example, orificebore upper portion 43 a has a smaller diameter than barrel headreceptacle 40, defining an upward facing shoulder 38 on which the lowerend of intake member neck 42 abuts. Orifice bore upper portion 43 a hasthe same diameter as the diameter of intake cavity 31. Orifice boreupper portion 43 a has a larger diameter than orifice bore lower portion43 b, defining an upward facing shoulder 44.

Barrel head 41 has a lower bore portion 48 extending downward fromorifice bore lower portion 43 b. Lower bore portion 48 has a largerdiameter than orifice bore lower portion 43 b, defining an annulardownward facing shoulder 50.

In this embodiment, the orifice at the lower end of intake cavity 31includes a nozzle 45 that fits within orifice bore portions 43 a and 43b. Nozzle 45 has an upper portion 45 a with an outer diameter that fitsclosely within orifice bore portion 43 a. A seal (not shown) or aninterference fit optionally may seal the outer diameter of nozzle upperportion 45 a to orifice bore upper portion 43 a. Nozzle 45 has adepending lower portion or neck 45 b with an outer diameter that extendsclosely through and below orifice bore lower portion 43 b. Thedifference between the outer diameters of nozzle upper portion 45 a andnozzle lower portion 45 b defines a downward facing annular surface thatabuts upward facing shoulder 44. A nut 46 may secure to threads on neck45 b to retain nozzle 45 in place. Nut 46 abuts downward facing shoulder50. Nozzle neck 45 b protrudes downward from downward facing shoulder 50within barrel lower bore portion 48.

Nozzle 45 has a converging orifice passage 47 a on its upper end thatconverges downward at a selected angle relative to axis 33. Acylindrical orifice passage 47 b joins the lower end of convergingorifice passage 47 a and extends at a constant diameter to the lower endof neck 45 b. The maximum diameter of converging orifice passage 47 a,which is at the upper end of nozzle 45, is the same as the diameter oforifice cavity 31.

A cylindrical barrel 49 has external threads on its upper end thatsecure to threads in barrel head bore lower portion 48. Barrel 49extends downward from barrel head 41, which may be considered to be apart of barrel 49. Barrel 49 and barrel head 41 have outer diametersthat are less than the inner diameter of housing 39, creating a barrelannulus 51 surrounding barrel 49. Barrel annulus 51 extends upward tothe lower ends of discharge passages 37. Barrel 49 has an inner diameterthat defines a barrel chamber 53. Barrel chamber 53 has a largerdiameter than orifice bore upper and lower portions 43 a, 43 b. Thediameter of barrel chamber 53 is illustrated as slightly less than thediameter of barrel head lower bore portion 48, but that may vary. Inthis example, the upper end of barrel 49 is spaced a short distancebelow barrel head downward facing shoulder 50.

As indicated by the solid line arrows, well fluid to be pumped flowsdown intake ports 35, intake cavity 31, and nozzle orifice passages 47a, b into barrel chamber 53. The flow area through nozzle orificepassages 47 a, b is much less than the flow area of intake cavity 31 andalso less than the combined flow areas of intake ports 35. The reductionin flow area creates a pressure change and increases the velocity of thewell fluid as it flows into barrel chamber 53. The pressure change tendsto cause some of the gas that may be entrained in the well fluid toseparate and flow back up intake cavity 31 and out intake ports 35, asindicated by the dashed line arrows. The gas flows back out intake ports35 into the annulus surrounding pump 11, and upward in the well. In thisexample, as will be explained subsequently, intake ports 35 and intakecavity 31 are always open regardless of whether pump 11 is in a wellfluid lifting stroke or an intake stroke.

Referring to FIG. 1B, in this example, a tubular barrel adapter 55secures by threads to the lower end of barrel 49 and may be consideredto be a part of barrel 49. Barrel adapter 55 extends downward andsecures by threads to a pump base 57. Housing 39 also secures by threadsto pump base 57. Barrel adapter 55 has a plurality of barrel ports 59 inits side wall. The inner diameter of barrel adapter 55 defines a lowerportion of barrel chamber 53, and barrel ports 59 communicate this lowerportion of barrel chamber 53 with barrel annulus 51.

In this embodiment, a fluid moving mechanism comprises a plungerassembly 61, which strokes up and down within barrel chamber 53. FIG. 1Bshows plunger assembly 61 in a lower or down stroke position. Aconnecting rod or motor drive shaft 67 secures to plunger assembly 61.Connecting rod 67 extends upward from a motor 69 that secures to thelower end of pump base 57. Motor 69 may be a linear motor of a typedescribed in published application US 2015/0176574. Alternately, motor69 could be an electrical motor that has a motion converter to convertrotary motion of its drive shaft to linear motion for connecting rod 67.Also, a pressure equalizer or seal section (not shown) for equalizingmotor lubricant pressure with well bore pressure could be connectedbetween motor 69 and pump 11.

Plunger assembly 61 has a middle portion 71 extending upward from alower portion of plunger assembly 61. Plunger middle portion 71 has anaxially extending plunger cavity 73. Plunger ports 75 in the side wallof plunger middle portion 71 communicate well fluid in plunger cavity 73with barrel annulus 51. The portion of the side wall containing plungerports 75 is smaller in outer diameter than the portions of plungerassembly 61 directly above and below.

Plunger assembly 61 has an upper plunger portion 77 that is a tubularmember with a bore that is an upward continuation of plunger cavity 73.A travelling valve 79 secures to the upper end of upper plunger portion77 for stroking movement with plunger assembly 61. Travelling valve 79has a valve element or ball 81 that closes when engaging a seat 83located above ball 81.

During operation of this embodiment, well fluid will always be presentin intake cavity 31, nozzle passage 47, and the upper portion of barrelchamber 53. Assuming that plunger assembly 61 is being moved upward byconnecting rod 67 from the position shown in FIG. 1B, travelling valve79 will be open and standing valve 21 (FIG. 1A) will be closed. Wellfluid in barrel chamber 53 flows downward into plunger cavity 73,filling plunger cavity 73. The well fluid entering plunger cavity 73causes downward flow of well fluid in intake cavity 31, resulting inseparation of gas at nozzle 45, as explained above. The gaseous portionsof the well fluid migrate back upward and out intake ports 35. Duringthis upstroke, well fluid in plunger cavity 73 is able to flow outplunger ports 75 into barrel chamber 53 below plunger assembly 61.

Typically, when plunger 61 is moving upward, some well fluid is pushedout nozzle 45 and into intake cavity 31. This upward flow causes orifice43 to develop back pressure in barrel chamber 53. During the upstroke,since there is a restriction of flow created at nozzle 45, additionalcompression of the well fluid is created between plunger assembly 61 andnozzle 45. This additional compression of the well fluid forces morewell fluid through plunger assembly 61 and also aids in forcing some ofthe gas back into pump intake ports 35.

As plunger assembly 61 is pulled downward by connecting rod 67 from thetop of the upstroke, travelling valve 79 closes, and plunger assembly 61will push well fluid in barrel chamber 53 below plunger assembly 61downward and out through barrel ports 59 into barrel annulus 51. Theforce caused by the downward movement of plunger assembly 61 forces wellfluid in barrel annulus 51 up through discharge passages 37 and opensstanding valve 23 to allow flow up into production tubing 13.

During the down stroke, the closed travelling valve 79 prevents downwardflow of well fluid in barrel chamber 53 into plunger cavity 73. However,well fluid entering intake ports 35 will still flow through intakecavity 31 and nozzle orifice passage 47 into barrel chamber 53. Gasseparation will thus occur at nozzle 45 both during the upstroke and thedown stroke. At or near the bottom of the down stroke, plunger ports 75will again register with barrel ports 59, communicating plunger cavity73 with barrel annulus 59. The well fluid in plunger cavity 73 thusflows from plunger cavity 73 and barrel annulus 59 into barrel chamber53. Travelling valve 79 opens at the bottom of the production stroke.This allows well fluid from intake cavity 31 and barrel chamber 53 tocommunicate with plunger cavity 73. Then, when plunger assembly 61 movesupward during the fill stroke, the fluid in barrel chamber 53 moves toplunger cavity 73 and barrel annulus 59.

In the alternate embodiment of FIG. 3, many of the features are the sameas in the first embodiment and will not be mentioned again. Componentsthat are the same and are mentioned have the same numerals as in FIGS. 1and 2. In FIG. 3, nozzle 45 (FIG. 2) is not used. Orifice 43 has orificebore portions 43 a and 43 b as in the first embodiment. Upward facingshoulder 44 is in a plane perpendicular to axis 33, defining orifice 43as a square edged orifice. In this example, orifice bore upper portion43 a has the same diameter as intake cavity 31. Because of the samediameters of orifice bore upper portion 43 a and intake cavity 31,upward facing shoulder 44 may be considered to be at the lower end ofintake cavity 31. A short downward converging section or upper bevel 87may be at the junction of bore lower portion 43 b with shoulder 44. Ashort downward diverging section or lower bevel 89 may be at the lowerend of bore lower portion 43 b.

Bore lower portion 43 b creates a pressure change and increases thevelocity of the well fluid flowing downward from intake cavity 31,causing a separation of gas at shoulder 44. Bore lower portion 43 b maycreate a greater pressure change and greater increase in velocity thanthe converging nozzle 45 (FIG. 2), to help separate gas from the liquid.However, the restrictive orifice arrangement of FIG. 3 may restrict theoverall flow rate of well fluid into the barrel chamber 53 more thanconverging nozzle 45.

Orifice 43 of the FIG. 3 should be sized, diameter and length, accordingto the anticipated flow and necessary pressure change through orifice43. Orifice bore portions 43 a, 43 b, as shown in FIG. 3 may beidentical to orifice bore portions 43 a, 43 b of FIG. 2. Subsequently,if a converging nozzle, such as nozzle 45 (FIG. 1A) is installed inorifice bore portions 43 a, 43 b, the size of the converging nozzlepassage 47 a, as well as the diameter and length of nozzle passage 47 bshould be sized according to the anticipated flow and necessary pressurechanges.

The present disclosure described herein, therefore, is well adapted tocarry out the objects and attain the ends and advantages mentioned, aswell as others inherent therein. While two embodiments of the disclosurehave been given for purposes of disclosure, numerous changes exist inthe details of procedures for accomplishing the desired results. Theseand other similar modifications will readily suggest themselves to thoseskilled in the art, and are intended to be encompassed within the scopeof the appended claims.

For example, the restrictive intake passage arrangement could be locatedin other parts of the intake passage. Also, the restrictive intakepassage arrangement could be incorporated with other types of pumps,even rotary types. More than one converging nozzle in series, or morethan one squared edged orifice, could be used. A separate andreplaceable orifice plate could be employed in the restrictive passagein the barrel head.

The invention claimed is:
 1. A well pump assembly, comprising: a pumphousing having a longitudinal axis; an intake member secured to the pumphousing; a discharge member secured to the pump housing and having adischarge passage; an intake passage in the intake member for drawingwell fluid into the pump; a fluid moving mechanism operatively locatedbetween the intake passage and the discharge passage to propel the wellfluid out the discharge passage; an orifice in the intake passage, theorifice having an orifice passage with a downstream direction convergingsection extending from the intake passage to a constant diametersection, the constant diameter section having a smaller diameter thanthe intake passage; wherein the orifice comprises: a nozzle containingthe orifice passage and secured within a downstream end of the intakepassage; and wherein the converging section of the orifice passage hasan upstream end with a diameter equal to a diameter of the downstreamend of the intake passage.
 2. The assembly according to claim 1, furthercomprising: a downstream direction diverging section joining andextending downward from the constant diameter section of the orificepassage.
 3. A well pump assembly, comprising: a pump housing having alongitudinal axis; an intake member secured to the pump housing; abarrel having a barrel head secured to and extending downward from theintake member, the barrel having a barrel bore; a plunger reciprocallycarried in the barrel bore; an intake passage extending coaxially in theintake member and the barrel head into the barrel bore above theplunger; an intake port extending from an exterior of the intake memberto the intake passage; and an orifice in the intake passage, the orificehaving an orifice passage with a downward converging section extendingdownward to a constant diameter section, the constant diameter sectionhaving a smaller diameter than the intake passage.
 4. The assemblyaccording to claim 3, wherein the orifice comprises: a nozzle containingthe orifice passage and secured within the intake passage.
 5. Theassembly according to claim 3, wherein the orifice comprises: a nozzlecontaining the orifice passage and secured within a lower end of theintake passage; and wherein the downward converging section of theorifice passage has a maximum diameter equal to a diameter of the lowerend of the intake passage.
 6. The assembly according to claim 3, whereinthe orifice comprises: a nozzle containing the orifice passage andsecured within a lower end of the intake passage, the nozzle having anozzle upper portion extending upward into the intake passage, thenozzle having a nozzle lower portion extending downward below the lowerend of the intake passage into the barrel bore.
 7. The assemblyaccording to claim 3, wherein the orifice comprises: a nozzle containingthe orifice passage and secured within a lower end of the intakepassage, the nozzle having a nozzle upper portion and a nozzle lowerportion, the nozzle upper portion having a larger outer diameter that isthe same as an outer diameter of the intake passage and greater than anouter diameter of the nozzle lower portion; the nozzle lower portionextending downward below the lower end of the intake passage into thebarrel bore; and the outer diameter of the nozzle lower portion beingsmaller than a diameter of the barrel bore.
 8. The assembly according toclaim 3, wherein the orifice comprises: an annular upward facingshoulder at a lower end of the intake passage; an orifice bore extendingthrough the upward facing shoulder; a nozzle containing the orificepassage, the nozzle having a nozzle upper portion and a nozzle lowerportion, the nozzle upper portion having a larger outer diameter than anouter diameter of the nozzle lower portion, defining a downward facingshoulder that rests on the upward facing shoulder; the outer diameter ofthe nozzle upper portion being the same as the diameter of the intakepassage; the outer diameter of the nozzle lower portion being the sameas the diameter of the orifice bore; and the nozzle lower portionprotruding below the orifice bore into the barrel bore.
 9. The assemblyaccording to claim 3, further comprising: a downward diverging lowersection joining and extending downward from the constant diametersection of the orifice passage.
 10. A well pump assembly, comprising: apump housing having a longitudinal axis; an intake member secured to thepump housing; a barrel having a barrel head secured to and extendingdownward from the intake member, the barrel having a barrel bore; aplunger reciprocally carried in the barrel bore; an intake passageextending coaxially in the intake member and the barrel head into thebarrel bore above the plunger; an intake port extending from an exteriorof the intake member to the intake passage; and a nozzle secured at alower end of the intake passage, the nozzle having an orifice passagewith a downward converging section extending downward to a constantdiameter section, the constant diameter section having a smallerdiameter than the intake passage.
 11. The assembly according to claim10, wherein: the downward converging section of the orifice passage hasan upper end with a diameter equal to a diameter of the intake passage.12. The assembly according to claim 10, wherein: the nozzle has a nozzleupper portion and a nozzle lower portion extending downward below thelower end of the intake passage into the barrel bore.
 13. The assemblyaccording to claim 10, wherein: the nozzle has a nozzle upper portionand a nozzle lower portion, the nozzle upper portion having an outerdiameter that is the same as a diameter of the intake passage andgreater than an outer diameter of the nozzle lower portion; the nozzlelower portion extends downward into the barrel bore; and the outerdiameter of the nozzle lower portion is smaller than a diameter of thebarrel bore.
 14. The assembly according to claim 10, further comprising:an annular upward facing shoulder at a lower end of the intake passage;an orifice bore extending through the upward facing shoulder; whereinthe nozzle has a nozzle upper portion with a larger outer diameter thanan outer diameter of a nozzle lower portion, defining a downward facingshoulder that rests on the upward facing shoulder; the outer diameter ofthe nozzle upper portion being the same as the diameter of the intakepassage; the outer diameter of the nozzle lower portion being the sameas the diameter of the orifice bore; and the nozzle lower portionprotruding below the orifice bore into the barrel bore.
 15. The assemblyaccording to claim 14, wherein an outer diameter of the annular upwardfacing shoulder is the same as a diameter of the intake passage.